Mapping waterway changes - adding/losing land

I am mapping a river and its changes (there will be a later followup topic on the best practice for mapping a much larger area of this river and its harbour once I understand the options here).

The following 2 images show an aerial view of the river in 1944 and the OHM map for the current river profile/shoreline, which currently has no start_date.

I can easily show in OHM the addition of land with time by adding a river area with no start-date and an end_date somewhere between 1944 and now. There seems to be no corresponding ‘land’ area shortcut that I can use to map the loss of land. Is the proper way to break the river into segments with their own start and and end dates? I suspect that the answer is YES once I consider the adjacent land features such as the mangrove areas, which also change with time, but it would be nice if there was a ‘lose land’ shortcut for minor changes.


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Yes, split up both the waterway way and the natural=water areas.

To keep the waterway ways coherent, you can join together the ways corresponding to a given time period into a type=waterway relation. There would be multiple such relations reflecting the different time periods. To keep them organized, you can add those relations to a type=chronology relation. But all this is optional; the renderer will do the right thing as long as you split up the features and tag them with dates.


@AndrewS_OHM - just following up here to make sure this answered your questions.

Mapping changes in river history is one of the coolest things about OHM, imo!! :slight_smile: